p65 Uncontrolled cell division (Cancer)

What Is Cancer?Cancer is a disease in which cells grow and divide uncontrollably, damaging the parts of the body around them. Cancer is something like weeds in a garden. Weeds can overrun the garden plants, robbing them of the space, sunlight, and water they need. Similarly, cancer cells can overrun normal cells.How Cancer BeginsScientists think that cancer begins when something damages a portion of the DNA in a chromosome. The damage causes a change in the DNA called a mutation. DNA contains all the instructions necessary for life. Damage to the DNA can cause cells to function abnormally.Normally, the cells in one part of the body live in harmony with the cells around them. Cells that go through the cell cycle divide in a controlled way. Cancer begins when mutations disrupt the normal cell cycle, causing cells to divide in an uncontrolled way. Without the normal controls on the cell cycle, the cells grow too large and divide too often.At first, one cell develops in an abnormal way. As the cell divides over and over, the repeated divisions produce more and more abnormal cells. In time, these cells form a tumor. A tumor is a mass of abnormal cells that develops when cancerous cells divide and grow uncontrollably.